Hydraulic bending press



Aug. 8, 1939. J; R. SHEPPARD HYDRAULIC BENDING PRESS Filed April 29. 1938 SSheets-Sheet 1 3 Sheets-Sheet 2 J92 Jezzfof: JZSgv/z l J I- J. R. SHEPPARD HYDRAULIC SENDING PRESS Filed April 29, 1938 Jdf Aug. 8, 1939.

8, 1939. J. R. SHEPPARD 7 2,169,113

HYDRAULIC BENDING PRESS Filed April 29, 1938 5 Sheets-Sheet s v lleys 1 atented Aug. 8, 1939 UNITED STATES PATENT OFFICE HYDRAULIC BENDING rncss Joseph R. Sheppard, Haddoniield, N. J., assignor to Charles F. Elmes Engineering Works, Chicago, 111., a corporation of Illinois Application April 29, 1938, Serial No. 205,137

8 Claims.

7 with each cylinder contained in its individual factors, however, which may cause one press ram to move somewhat faster than the other. Such factors may be variations in flow of pressure liquid to the actuating cylinders, friction of the different packings in the press rams, and certaintypes of pressing conditions. If one press ram moves faster than the other, there is undesirable angular travel of the pressing or moving platen, with consequent binding or twisting effect in the guide members which areusually provided between the pressing platen and the press housings. It is the principal object of this invention to provide a two-cylinder hydraulic press in which the two pressing rams will be assured a uniform rate .of travel. The invention-contemplates also an arrangement of guide members to accommodate any adjustment of ram travel, whether the two rams move together or one moves in advance of the other.

The present invention contemplates a press construction in which, by suitable pre-charging of one of the cylinders, the movable platen can be made to advance to its work with its pressing surface at an angle to the stationary platen. The common operation would, of course, be with the pressing surfaces of the movable and stationary platens held parallel to each other. If the press is used as a shearing machine, instead of the normal plate bending purpose, then it may be advantageous to have one end of the moving platen closer to the stationary platen than the other.

The present guide construction is such that no distortion or twisting effect will result from having the pressing surface of the movable platen set at an angle to the stationary platen.

It should be understood that the press as shown in the drawings may be operated from any customary supply of hydraulic pressure, such as an individual pumping unit or an accumulator system. The features and advantages of the invention will appear more fullyas the description proceeds in connection with the accompanying drawings, wherein a preferred form of the invention is shown.

It is to be understood, however, that the drawings and description are illustrative only, and are not to be considered as limiting the invention except insofar as it is limited by the claims.

In the drawings, Fig. 1 is a somewhat diagrammatic view illustrating the arrangement of the hydraulic cylinders and the hydraulic fluid circuit employed therewith;

Fig. 2 is a front view of one end housing of the press;

Fig. 3 is a sectional view taken on the line 3--3 of Fig. 2;

Fig. 4 is a sectional view taken on the line l4 of Fig. 3, and

Fig. -5 is an enlarged sectional view taken on the line 5-5 of Fig. 3.

Referring now tothe drawings, and particularly to Fig. 1, the press is shown as having a station- I ary platen 6 and a movable platen I. The movable platen I is connected by pins 8 and 9 to two guides-- in and H. The guides I0 and H are adapted to be engaged by press rams l2 and 13.

The press rams i2 and 13 are mounted in cylinders l4 and I5.

It will be noted that the cylinder I4 accommodates a differential ram in which the ram 12 has an enlarged end 16 which is twice the area in cross section as that of the main ram portion l2. The enlarged end i6 is desirably in the form of a pressure tight piston so that no leakage can take place from the space I! in the cylinder It to the space It.

The press cylinder l5 accommodates the ram 13 which has the same area as the ram [2, space l9 being provided in the cylinder I5 so that the pressure fluid may he introduced above the ram 13.

The space I8 of cylinder I4 is connected to the space IQ of the cylinder 15 by suitable piping 20. This piping is connected by a, pipe2l through a check valve 22 to a reservoir 23. The check valve 22 is so disposed as to permit flow of fluid from the reservoir 23 to the spaces l8 and I9. However, the position of the check valve 22 is such as to prevent flow from the cylinders" back into the reservoir 23. The reservoir 23 is connected by a pipe 24 to a suitable control valve 25 which is adapted to be actuated by a COIltIul lever 26. The valve 25 has an inlet pipe 21 leading from a pump 23 which is driven by a motor 29. The pump "is connected by a pipe 30 to the reservoir iii ' known structure in the art, and it is believed that further description thereof is unnecesary.

The pipe 32 has two branches 33 and 3 3 which communicate with two pull-back cylinders 35 and 35. The cylinders 35 and 36 have pistons 3t 'and 36, respectively, connected to the movable platen l by stems 39 and 10.

The operation of the fiuid cycle is as follows: When both rams i2 and iii are in the up position as shown in the drawings, the lower space it of the cylinder i4 and the space IQ of the cylinder l 5, together with the interconnecting pipes 20 and ti, are kept completely filled with liquid entering through the check valve 22. If the valve 25 is operated to admit liquid to the space N, then the piston i6 will be forced downward, and in consequence will force liquid from the space i8 over into the space IQ of the cylinder 95. As hereinbefore stated, the rams i2 and l3are of the same area in cross section. Furthermore, the piston I6 is twice the area of the ram i2. Since the combined areas of pistons i2 and i 3 are equal to the area of the piston it, both the rams i2 and it will be caused to travel at an equal speed and for an equal distance. As pressure is applied to the top of the piston iii, each ram will exert one-half of the total pressure applied on the top of the piston It. On the reverse stroke the valve 25 is, of course, set to direct fluid under pressure beneath the pull-back pistons 3i and 3t. At the same time, the pipe 3! is by-passed by the valve 25 into communication with the pipe 25 so as to permit liquid to return to the reservoir 23 from the space i'i over the piston 56.

In order to produce movement of one end of the platen l ahead of the other, a valve iii connecting pipe 2i with pipe 2 3 may be used, precharging the pipe 20 and the spaces i8 and it so that the ram i3 is advanced below the ram i2. The valve 4| may then be closed and, when the operation hereinabove described takes place, the same relative positions of the rams l2 and itlwill be maintained throughout the structure. The ram 03 will advance at the same speed as the ram i2, but will be started at-a lower level, thus causing the platen i to assume an angular-- position with respect to the stationary platen 6.

Referring now to the construction of the press, this is best shown in Figs. 2 5. It is to be understood, ofcourse, that Fig. 2 illustrates one end of the press and that the other end, shown at the left in Fig. 1, is substantially a duplicate thereof except for the different cylinder 05 and ram it.

The end housing of the press comprises two side plates 42 and 33 which are connected together by cross tie members 4 3 and t5, preferably welded to the side plates t2 and 43. The lower platen 6 is bolted directly to a plate 46 which is welded to the side plates 42 and 43. The upper platen i has elongated openings 41 and 48 to receive the pins such as pin 8 on the guide Ill. The guide iii has portions 49 and 5G projecting from the opposite side edges thereof and adapted to beguided in suitable guideways provided on the plates 42 and as. To form the guideways plate t2 has a vertically running bar iii at the front edge thereof, secured in place by bolts 52 and adapted to engage a shoulder 53 arcane on the portion it. The plate 42 has a bar M bolted thereto by bolts 55. The bar 54 engages a shoulder 56 on the portion 50. A bar 5'6 is welded to the plate 43 to the rear of the projection 49 .and the bar 5% is welded to the plate 32 to the rear of the projection 50. The rear edges of the projections t9 and 50 are bevelled, as shown at 59 and 68. In order to hold the projections t9 and 50 up against the bars 5i and 54, I provide adjustable gibs Bi and 62 between the bars 57 and 58 and the bevelled faces 59 and Mi. These adjustable gibs have bevelled faces engaging the faces 59 and Gil. Screw bolts $3 and as are utilized to clamp the members 6i and ti. in place. It is believed to be clear that any wear can be taken up by moving the adjustable gibs 6i and 52 inward and putting shims behind them. The pull-back cylinder 36 is mounted to the side plates 62 and 43, and the stem 40 is passed through a rearwardly extending portion 65 of the guide it. It is secured to the guide It by lock nuts 56. The moving platen I is held on the pin 8 by a washer El and a screw bolt 68.

The side frames 42 and 43 also mount the cylinder M. The cylinder is provided with a flanged end 69 beneath which the side plates M and t3 engage. A front plate 10 is bolted to the front edges of the side plates 62 and it.

The platen i has curved upper ram-engaging faces Ii and 72 (see Figs. 1 and 2). The surfaces ii and i2 are so curved as to take care of any angular disposition of the movable platen i as may be desired. The rams i2 and it fit into the guides iii and H as shown best in Figs. 2 and 3 so as to directly engage the surfaces it and 172.

From the above description it is believed that the construction and operation of this device will. be readily apparent to those skilled in this art. Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

i. In a hydraulic press of the character described, comprising a stationary platen, a moving platen, guide means for said moving platen, spaced rams operable to apply pressure to the moving platen and force it toward the stationary platen, cylinders for said rams and means for causing the rams to be advanced the same distance at the same speed under all conditions, said last named means comprising a piston on one of the rams having an area equal to the sum of the areas of said rams, .the cylinder for said last named ram having a space beneath the piston equal in cross section to the area of the other ram,- said space beneath the piston being connected with the hydraulic liquid space in the cylinder for the other ram.

2. In a hydraulic press of the character described, comprising a stationary platen, a moving platen, guide means for said moving platen, spaced rams operable to apply pressure to the moving platen and force it toward the stationary platen, cylindersdor said rams and means for causing the ramp to be advanced the samedistance at the same speed under all conditions, said last named means comprising a piston on one of the rams having an area equal to the sum of the areas of said rams, the cylinder for said last named ram having a space beneath the piston equal in cross section to the areaof the other ram, said space beneath the piston being connected with the hydraulic liquid space in the cylinder for the other ram, a supply conduit for filling said spaces and the connection between them with liquid, a check valve in said conduit to prevent return of fluid from said spaces, and a valved by-pass around said check valve whereby to supply liquid to and remove liquid from said spaces.

3. In a hydraulic press of the character described, a frame, a pair of cylinders thereon, rams in said cylinders, a piston in one cylinder having a cross-sectional area equal to the sum of the cross-sectional areas of said rams, means including said cylinders providing a sealed liquid chamber including the spaces around said rams, and means to apply pressure to the piston whereby to cause equal advancements of both rams at the same speed.

4. In a hydraulic press of the character de scribed, a frame, a 'pair of .cylinders thereon, rams in said cylinders, a piston in one cylinder having a cross-sectional area equal to of the cross-sectional areas of said rams, means including said cylinders providing a sealed liquid chamber including the spaces around said rams, means to apply pressure to the piston whereby to cause equal advancements of both rams at the same speed, and means tions of said rams comprising means to vary the amount of liquid in said sealed chamber.

5. In a hydraulic press of the character described, a frame, a pair of cylinders thereon, rams in said cylinders, a piston in one cylinder having a cross-sectional area equal to the sum of the cross-sectional areas of said rams, means including said cylinders providing asealed liquid chamber including the spaces around said rams, means to apply pressure to the piston whereby to cause equal advancements of both rams at the same speed, and means to vary the relative positions of said rams comprising means to vary the the sum to vary the relative posi-v amount of liquid in said sealed chamber, said last named means comprising a liquid supply conduit having a check valve and a valved by-pass around the check valve.

6. In a hydraulic press of the character described, a frame, a pair of cylinders thereon,

rams in said cylinders,-a piston in one cylinder having a cross-sectional area equal to the sum of the cross-sectional areas of said rams, means including said cylinders providing a sealed liquid chamber including the spaces around said rams, means to apply pressure to the piston whereby to cause equal advancements of both rams at the same speed, a movable platen adapted to be advanced by said rams, a guide associated with each ram and slidably mounted in said frame, and means pivotally mounting said platen on each of the guide means, said mounting means comprising a pin and elongated slot connection.

'1. In a hydraulic press of the character de-' scribed, a frame, a pair ofcylinders thereon, rams in said cylinders, a movable plat-en adapted to be advanced by said rams, a guide associated with each ram and slidably mounted in said frame, and means pivotally mounting said platen on each of the guide means, said mountingmeans comprising a pin and elongated slot connection.

8. In a hydraulic press of the character described, a frame, a pair ofcylinders thereon, rams in said cylinders, a movable platen adapted to be advanced by said rams, a guide associated with each ram and slidably mounted in said frame, and means pivotally mounting said platen on each of the guide means, said mounting means comprising a pin and elongated slot connection, said platen having convex bearing portions adapted to receive the pressure from said rams.

JOSEPH R. SHEPPARD. 

